All categories

2 years ago

Mark bought 12 boxes of paper clips and 10 packages of index cards for a

Mathematics

1 answer:

Nata [24]2 years ago

8 0

Answer:

paper clips = $1.85

index cards = $3.95

Step-by-step explanation:

Mark

12 paper clips = x

10 index cards = y

$61.70 total

Janice

15 paper clips = x

7 index cards = y

$55.40 total

12x + 10y = 61.70

15x + 7y = 55.40

*** you want to cancel out one of the letters

(12x + 10y = 61.70) * -7

(15x + 7y = 55.40) * 10

-84x -70y = -431.9

150x + 70y = 554.0

-84x -70y = -431.9

66x + 0 = 122.1

66x = 122.1

x = 122.1 ÷ 66

x = 1.85

plug it back in

15(1.85) + 7y = 55.40

27.75 + 7y = 55.40

7y = 55.40 - 27.75

7y = 27.65

y = 27.65 ÷ 7

y = 3.95

You might be interested in

A=4, b=2,c=-1 find value of a-b+c

777dan777 [17]

Answer:

Step-by-step explanation:

Substitute the value of the variable into the expression and simplify.

4-2-1=1

7 0

3 years ago

Read 2 more answers

Write the given differential equation in the form L(y) = g(x), where L is a linear differential operator with constant coefficie

melamori03 [73]

Answer:

The complete solution is

$\therefore y= Ae^{3x}+Be^{-\frac13 x}-\frac43$

Step-by-step explanation:

Given differential equation is

3y"- 8y' - 3y =4

The trial solution is

$y = e^{mx}$

Differentiating with respect to x

$y'= me^{mx}$

Again differentiating with respect to x

$y''= m ^2 e^{mx}$

Putting the value of y, y' and y'' in left side of the differential equation

$3m^2e^{mx}-8m e^{mx}- 3e^{mx}=0$

$\Rightarrow 3m^2-8m-3=0$

The auxiliary equation is

$3m^2-8m-3=0$

$\Rightarrow 3m^2 -9m+m-3m=0$

$\Rightarrow 3m(m-3)+1(m-3)=0$

$\Rightarrow (3m+1)(m-3)=0$

$\Rightarrow m = 3, -\frac13$

The complementary function is

$y= Ae^{3x}+Be^{-\frac13 x}$

y''= D², y' = D

The given differential equation is

(3D²-8D-3D)y =4

⇒(3D+1)(D-3)y =4

Since the linear operation is

L(D) ≡ (3D+1)(D-3)

For particular integral

$y_p=\frac 1{(3D+1)(D-3)} .4$

$=4.\frac 1{(3D+1)(D-3)} .e^{0.x}$ [since $e^{0.x}=1$ ]

$=4\frac{1}{(3.0+1)(0-3)}$ [ replace D by 0 , since L(0)≠0]

$=-\frac43$

The complete solution is

y= C.F+P.I

$\therefore y= Ae^{3x}+Be^{-\frac13 x}-\frac43$

4 0

2 years ago

Suppose that 14 inches of wire costs 84 cents.

mamaluj [8]

Answer: 222 cents

Step-by-step explanation: 84/14 = 6 This is the unit rate.

6 x 37 = 222

6 0

1 year ago

Read 2 more answers

Tracy was given a bag of 250 colored marbles .She randomly chose marble , recorded its color in the table ,and returned it to th

jok3333 [9.3K]

Answer:

Did you ever figured it out?

Step-by-step explanation:

5 0

3 years ago

Choose the correct simplification of the expression (−2x + 8y)(9x − 3y).

Romashka-Z-Leto [24]

For these kinds of expressions use FOIL (first, outside, inside, last).

-2x • 9x = -18x^2
-2x • -3y = 6xy
8y • 9x = 72 xy
8y • -3y = -24y^2

Now combine them all:

-18x^2 + 78xy - 24y^2

6 0

3 years ago

Read 2 more answers